/^ 



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f* rt 



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Fig. 67.— Lumbar puncture with Strauss needle, illustrating the method of intra- 

 spinal injection by the gravity method. After introduction of needle, the obturator, 

 O, is withdrawn to point shown in cut. This permits of the spinal fluid to rise in 

 attached pipette, P, graduated in hundredths of a cubic centimetre, thereby permitting 

 of the determination of the degree of intraspinal pressure. The desired amount of spinal 

 fluid may then be collected in a test-tube held under the exit, M, by removing the 

 metallic plug. The plug is then reinserted, the pressure noted and the obturator 

 partially replaced. The graduated pipette or tube, P. is then disconnected from the 

 needle at C and the rubber tubing, T", leading from the re.?ervoir containing the serum 

 attached to the needle. The obturator is again withdrawn as far as it will go and the 

 serum allowed to flow in. An assistant with his arm around the patient's neck, as illus- 

 trated, and his fist in the epigastric region can do much to steady the patient and assist 

 him to properly arch his spine. 



